Surface-treating agent comprising fluoropolymer

ABSTRACT

A surface-treating agent comprises a fluoropolymer comprising (A) repeating units derived from a fluorine-containing monomer of the formula:  
                 
 
(B) repeating units derived from a monomer free from a fluorine atom, and (C) optionally, repeating units derived from a crosslinkable monomer. The surface treating agent is excellent in water repellency, oil repellency and unsusceptibility to fouling even when the side chains are C 4  or lower fluoroalkyl groups.

TECHINICAL FIELD

The present invention relates to a polymer and a treatment which impartexcellent water repellency, oil repellency and soil resistance to atextile, a masonry, an electrostatic filter, a dust protective mask, anda part of fuel cell.

BACKGROUND ART

Hitherto, a fluorine-containing acrylate polymer is used as an activecomponent of a water- and oil-repellent agent. Side chain fluoroalkylgroups in practically used fluorine-containing acrylate monomers usuallyhave at least 8 carbon atoms. There is a defect that thefluorine-containing acrylate monomer is excessively hydrophobic sincethe length of the fluoroalkyl chain is long. The excessivehydrophobicity has caused various problems on the preparation andproperties of the fluorine-containing acrylate polymer.

When an emulsion polymerization is used for the preparation of thefluorine-containing acrylate polymer, there are problems thatemulsifiers should be used in a large amount and the types of theemulsifiers are limited, and that an auxiliary solvent should be usedbecause of poor solubility with another fluorine-free monomer. When asolution polymerization is used for the preparation of thefluorine-containing acrylate polymer, there was the problem that thefluorine-containing acrylate monomer has low solubility in apolymerization solvent so that a sufficient monomer solution cannot beobtained.

As to the properties of the fluorine-containing acrylate polymer, thereis the problem that sufficient water repellency cannot be imparted tothe substrate. This problem seems to be caused by excessivehydrophobicity given by the long fluoroalkyl group.

Various up-to-date research results indicate that in view of thepractical treatment of fibers with the surface treatment agent(particularly the water- and oil-repellent agent), the important surfaceproperty is not a static contact angle, but is a dynamic contact angle,particularly a reversing contact angle. That is, the advancing contactangle of water is not dependent on the carbon number of the fluoroalkylside chain, but the reversing contact angle of water in the case ofcarbon number of at most 7 is remarkably low than that in the case ofcarbon number of at least 8. In correspondence to this, an X rayanalysis shows that the side chain crystallizes when the carbon numberof side chain is at least 7. It is known that the practical waterrepellency has the relationship with the crystallization of the sidechain and that motility of the surface treatment agent molecules is animportant factor for revelation of the practical performances (forexample, MAEKAWA Takashige, FINE CHEMICAL, Vol. 23, No. 6, page 12(1994)). Accordingly, it is believed that the acrylate polymer havinglow carbon number of fluoroalkyl group in the side chain which is atmost 7 (particularly at most 6) has low crystallinity so that thepolymer cannot satisfy the practical performances (particularly waterrepellency).

JP-A-63-90588, JP-A-63-99285 and JP-A-01-315471 disclose that afluorine-containing acrylate polymer wherein the alpha-position issubstituted with fluorine, chlorine or the like has good properties suchas good adhesion to a substrate, high strength of a film and good water-and oil-repellency. These publications describe that the fluoroalkylgroup used in Examples has at least 8 carbon atoms and does not suggestto use the acrylate monomer having the fluoroalkyl group having at most6 carbon atoms.

Recent study results (EPA Report “PRELIMINARY RISK ASSESSMENT OF THEDEVELOPMENTAL TOXICITY ASSOCIATED WITH EXPOSURE TO PERFLUOROOCTANOICACID AND ITS SALTS” (http://www.epa.gov/opptintr/pfoa/pfoara.pdf)) andthe like clarify that a PFOA (perfluorooctanoic acid) doubtfully has apotential risk of environmental load. EPA (Environmental ProtectionAgency of USA) announced on Apr. 14, 2003 that the EPA intensifies thescientific investigation on PFOA.

On the other hand, Federal Register (FR Vol. 68, No. 73/Apr. 16, 2003[FRL-2303-8]) (http://www.epa.gov/opptintr/pfoa/pfoafr.pdf), EPAEnvironmental News for release Monday April, 2003 “EPA —INTENSIFIESSCIENTIFIC INVESTIGATION OF A CHEMICAL PROCESSING AID”(http://www.epa.gov/opptintr/pfoa/pfoaprs.pdf), and EPA OPPT FACT SHEETApr. 14, 2003 (http://www.epa.gov/opptintr/pfoa/pfoafacts.pdf) announcedthat a “telomer” may possibly metabolize or decompose to PFOA. It isalso announced that the “telomer” is used in a large number ofcommercial products including fire fighting foams, care products andcleaning products as well as soil, stain and grease resistant coating oncarpets, textiles, paper, and leather.

DISCLOSURE OF THE INVENTION Technical Problems to be Solved by theInvention

An object of the present invention is to provide a fluorine-containingacrylate polymer having excellent water repellency, oil repellency, soilresistance and stain adhesion resistance, even when a side chain is ashort fluoroalkyl group having at most 6 carbon atoms.

Another object of the present invention is to provide a substitutecompound having chemical skeleton structure which is different from theabove-mentioned “telomer”.

Measures for Solving Problems

The present invention provides a surface treatment agent comprising afluorine-containing polymer comprising:

-   (A) repeating units derived from a fluorine-containing monomer of    the formula:    -   wherein X is a fluorine atom, a chlorine atom, a bromine atom, a        iodine atom, a CFX¹X² group (wherein X¹ and X² is a hydrogen        atom, a fluorine atom or a chlorine atom), a cyano group, a        linear or branched fluoroalkyl group having 1 to 20 carbon        atoms, a substituted or unsubstituted benzyl group, or a        substituted or unsubstituted phenyl group,    -   Y is an aliphatic group having 1 to 10 carbon atoms, an aromatic        or cycloaliphatic group having 6 to 10 carbon atoms,    -   a —CH₂CH₂N(R¹)SO₂— group (wherein R¹ is an alkyl group having 1        to 4 carbon atoms) or    -   —CH₂CH(OY¹)CH₂— group (wherein Y¹ is a hydrogen atom or an        acetyl group),    -   Rf is a linear or branched fluoroalkyl group having 1 to 6        carbon atoms,-   (B) repeating units derived from a monomer free from a fluorine    atom, and-   (C) optionally, repeating units derived from a crosslinkable    monomer.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

The fluorine-containing polymer constituting the surface treatment agentof the present invention is a copolymer comprising

(a) the fluorine-containing monomer of the formula (I) wherein analpha-position is substituted by a X group,

(b) the monomer free from a fluorine atom, and

optionally present, (c) the crosslinkable monomer.

The repeating units (A) are derived from (a) the fluorine-containingmonomer of the formula (I). In the formula (I), the Rf group ispreferably a perfluoroalkyl group. The carbon number of the Rf group isfrom 1 to 6, for example, from 1 to 4.

Y is preferably an aliphatic group having 1 to 10 carbon atoms, anaromatic group or cycloaliphatic group having 6 to 10 carbon atoms, a—CH₂CH₂N(R¹)SO₂— group (R¹ is an alkyl group having 1 to 4 carbon atoms)or a —CH₂CH(OY¹)CH₂— group (Y¹ is a hydrogen atom or an acetyl group).The aliphatic group is preferably an alkylene group (particularly thecarbon number is from 1 to 4, for example, 1 or 2). The aromatic groupand cycloaliphatic group may be substituted or unsubstituted.

Examples of fluorine-containing monomer (a) are as follows:

wherein Rf is a linear or branched fluoroalkyl group having 1 to 6carbon atoms.

The repeating units (B) are derived from (b) the monomer free from afluorine atom. The monomer (b) is preferably a fluorine-free monomerhaving a carbon-carbon double bond. The monomer (b) is preferably avinyl monomer which is free from fluorine. The fluorine atom-freemonomer (b) is generally a compound having one carbon-carbon doublebond. Preferable examples of the fluorine atom-free monomer (b) include,for example, ethylene, vinyl acetate, vinylidene halide, acrylonitrile,styrene, polyethyleneglycol (meth)acrylate, polypropyleneglycol(meth)acrylate, methoxypolyethyleneglycol (meth)acrylate,methoxypolypropyleneglycol (meth)acrylate, vinyl alkyl ether andisoprene. The fluorine atom-free monomer (b) is not limited to theseexamples.

The fluorine atom-free monomer (b) may be a (meth)acrylate ester havingan alkyl group. The number of carbon atoms of the alkyl group may befrom 1 to 30, for example, from 6 to 30, e.g., from 10 to 30. Forexample, the fluorine atom-free monomer (b) may be acrylates of thegeneral formula:CH₂═CA¹COOA²wherein A¹ is a hydrogen atom or a methyl group, and A² is an alkylgroup represented by C_(n)H₂₊₁ (n=1 to 30).

The repeating units (C) are derived from the crosslinkable monomer (c).The crosslinkable monomer (c) may be a fluorine-free monomer having atleast two reactive groups and/or carbon-carbon double bonds. Thecrosslinkable monomer (c) may be a compound having at least twocarbon-carbon double bonds, or a compound having at least onecarbon-carbon double bond and at least one reactive group. Examples ofthe reactive group include a hydroxyl group, an epoxy group, achloromethyl group, a blocked isocyanate group, an amino group and acarboxyl group.

Examples of the crosslinkable monomer (c) include diacetoneacrylamide,(meth)acrylamide, N-methylolacrylamide, hydroxymethyl(meth)acrylate,hydroxyethyl(meth)acrylate, 3-chloro-2-hydroxypropyl(meth)acrylate,N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, butadiene, chloroprene and glycidyl (meth)acrylate, towhich the crosslinkable monomer is not limited.

The copolymerization with the monomer (b) and/or the monomer (c) canoptionally improve various properties such as water- and oil-repellencyand soil resistance; cleaning durability and washing durability of saidrepellency and resistance; solubility in solvent; hardness; and feeling.

In the fluorine-containing polymer,

the amount of the fluorine atom-free monomer (b) may be from 0.1 to 100parts by weight, for example, from 0.1 to 50 parts by weight, and

the amount of the crosslinkable monomer (c) may be at most 50 parts byweight, for example, at most 20 parts by weight, particularly, from 0.1to 15 parts by weight,

based on 100 parts by weight of the fluorine-containing monomer (a).

The fluorine-containing polymer can be produced as follows.

In a solution polymerization, there can be used a method of dissolvingthe monomer(s) into an organic solvent in the presence of apolymerization initiator, replacing the atmosphere by nitrogen, andstirring the mixture with heating at the temperature within the rangefrom 30° C. to 120° C. for 1 hour to 10 hours. Examples of thepolymerization initiator include azobisisobutyronitrile, benzoylperoxide, di-tert-butyl peroxide, lauryl peroxide, cumene hydroperoxide,t-butyl peroxypivalate and diisopropyl peroxydicarbonate. Thepolymerization initiator may be used in the amount within the range from0.01 to 20 parts by weight, for example, from 0.01 to 10 parts byweight, based on 100 parts by weight of total of the monomers.

The organic solvent is inert to the monomer(s) and dissolves themonomer(s), and examples thereof include acetone, chloroform, HCHC225,isopropyl alcohol, pentane, hexane, heptane, octane, cyclohexane,benzene, toluene, xylene, petroleum ether, tetrahydrofuran, 1,4-dioxane,methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butylacetate, 1,1,2,2-tetrachloroethane, 1,1,1-trichloroethane,trichloroethylene, perchloroethylene, tetrachlorodifluoroethane andtrichlorotrifluoroethane. The organic solvent may be used in the amountwithin the range from 50 to 2,000 parts by weight, for example, from 50to 1,000 parts by weight, based on 100 parts by weight of total of themonomers.

In an emulsion polymerization, there can be used a method of emulsifyingmonomers in water in the presence of a polymerization initiator and anemulsifying agent, replacing the atmosphere by nitrogen, andpolymerizing with stirring, for example, at the temperature within therange from 50° C. to 80° C. for 1 hour to 10 hours. As thepolymerization initiator, for example, water-soluble initiators (e.g.,benzoyl peroxide, lauroyl peroxide, t-butyl perbenzoate,1-hydroxycyclohexyl hydroperoxide, 3-carboxypropionyl peroxide, acetylperoxide, azobisisobutyl-amidine dihydrochloride,azobisisobutyronitrile, sodium peroxide, potassium persulfate andammonium persulfate) and oil-soluble initiators (e.g.,azobisisobutyronitrile, benzoyl peroxide, di-tert-butyl peroxide, laurylperoxide, cumene hydroperoxide, t-butyl peroxypivalate and diisopropylperoxydicarbonate) are used. The polymerization initiator may be used inthe amount within the range from 0.01 to 10 parts by weight based on 100parts by weight of the monomers.

In order to obtain a polymer dispersion in water, which is superior instorage stability, it is desirable that the monomers are atomized inwater by using an emulsifying device capable of applying a strongshattering energy (e.g., a high-pressure homogenizer and an ultrasonichomogenizer) and then polymerized with using the oil-solublepolymerization initiator. As the emulsifying agent, various emulsifyingagents such as an anionic emulsifying agent, a cationic emulsifyingagent and a nonionic emulsifying agent can be used in the amount withinthe range from 0.5 to 20 parts by weight based on 100 parts by weight ofthe monomers. When the monomers are not completely compatibilized, acompatibilizing agent (e.g., a water-soluble organic solvent and alow-molecular weight monomer) capable of sufficiently compatibilizingthem is preferably added to these monomers. By the addition of thecompatibilizing agent, the emulsifiability and polymerizability can beimproved.

Examples of the water-soluble organic solvent include acetone, methylethyl ketone, ethyl acetate, propylene glycol, dipropylene glycolmonomethyl ether, dipropylene glycol, tripropylene glycol and ethanol.The water-soluble organic solvent may be used in the amount within therange from 1 to 50 parts by weight, e.g., from 10 to 40 parts by weight,based on 100 parts by weight of water. Examples of the low-molecularweight monomer include methyl methacrylate, glycidyl methacrylate and2,2,2-trifluoroethyl methacrylate. The low-molecular weight monomer maybe used in the amount within the range from 1 to 50 parts by weight,e.g., from 10 to 40 parts by weight, based on 100 parts by weight oftotal of monomers.

The surface treatment agent of the present invention is preferably inthe form of a solution, an emulsion or an aerosol. The surface treatmentagent generally comprises the fluorine-containing polymer and a medium(particularly a liquid medium, for example, an organic solvent and/orwater). The concentration of the fluorine-containing polymer in thesurface treatment agent may be, for example, from 0.1 to 50% by weight.

The surface treatment agent can be applied to a substrate to be treatedby a know procedure. Usually, the surface treatment agent is diluted ordispersed with an organic solvent or water, is adhered to surfaces ofthe substrate by a well-known procedure such as an immersion coating, aspray coating and a foam coating, and is dried. If necessary, thesurface treatment agent is applied together with a suitable crosslinkingagent, followed by curing. It is also possible to add other surfacetreatment agents (for example, a water repellent agent and an oilrepellent agent), or mothproofing agents, softeners, antimicrobialagents, flame retardants, antistatic agents, paint fixing agents,crease-proofing agents, etc. to the surface treatment agent of thepresent invention. For the immersion coating, the concentration of thefluorine-containing compound in the treatment liquid contacted with thesubstrate may be from 0.05 to 10% by weight, based on the treatmentliquid. For the spray coating, the concentration of thefluorine-containing compound in the treatment liquid may be from 0.1 to5% by weight, based on the treatment liquid. A stain blocker may beused. When the stain blocker is used, it is preferable to use an anionicemulsifier or a nonionic surfactant.

The substrate to be treated with the surface treatment agent (forexample, a water- and oil-repellent agent) of the present inventioninclude a textile, masonry, a filter (for example, an electrostaticfilter), a dust protective mask, a part of fuel cell (for example, agaseous diffusion electrode and a gaseous diffusion support), glass,paper, wood, leather, fur, asbestos, brick, cement, metal and oxide,ceramics, plastics, a coated surface and a plaster. The textile may beparticularly a carpet. The textile has various examples. Examples of thetextile include animal- or vegetable-origin natural fibers such ascotton, hemp, wool and silk; synthetic fibers such as polyamide,polyester, polyvinyl alcohol, polyacrylonitrile, polyvinyl chloride andpolypropylene; semi-synthetic fibers such as rayon and acetate;inorganic fibers such as glass fiber, carbon fiber and asbestos fiber;and a mixture of these fibers. The treatment agent of the presentinvention is excellent in resistance in a detergent liquid and brushing(mechanical), it can be suitably used for carpet made from nylon orpolypropylene.

The textile may be in any form such as a fiber, a fabric and the like.When the carpet is treated with the surface treatment agent of thepresent invention, the carpet may be formed after treating fibers oryarns with the surface treatment agent, or the formed carpet may betreated with the surface treatment agent.

EXAMPLES

The following Examples further illustrate the present invention indetail but are not to be construed to limit the scope thereof.

Shower Water Repellency Test

The shower water repellency was expressed by water repellency No. (asshown in the below-described Table 1) conducted according to JIS-L-1092.TABLE 1 Water repellency No. State 5 No wet or adhesion on surface 4Slight wet or adhesion on surface 3 Partial wet on surface 2 Wet onwhole surface 1 Wet on front and back whole surfacesWater-Repellency Test

A treated fabric is stored in a thermo-hygrostat having a temperature of21° C. and a humidity of 65% for at least 4 hours. A test liquid(isopropyl alcohol (IPA), water, and a mixture thereof, as shown inTable 2) which has been also stored at 21° C. is used. The test isconducted in an air-conditioned room having a temperature of 21° C. anda humidity of 65%. A droplet of the test liquid in an amount of 0.05 mLis softly dropped by a micropipette on the fabric. If the dropletremains on the fabric after standing for 30 seconds, the test liquidpasses the test. The water-repellency is expressed by a pointcorresponding to a maximum content (% by volume) of isopropyl alcohol(IPA) in the test liquid which passes the test. The water-repellency isevaluated as twelve levels which are Fail, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9and 10 in order of a poor level to an excellent level. TABLE 2Water-repellency test liquid (% by volume) Isopropyl Point alcohol Water10 100 0 9 90 10 8 80 20 7 70 30 6 60 40 5 50 50 4 40 60 3 30 70 2 20 801 10 90 0 0 100 Fail Inferior to isopropyl alcohol 0/water 100Oil-Repellency Test

A treated fabric is stored in a thermo-hygrostat having a temperature of21° C. and a humidity of 65% for at least 4 hours. A test liquid (shownin Table 3) which has been also stored at 21° C. is used. The test isconducted in an air-conditioned room having a temperature of 21° C. anda humidity of 65%. A droplet of the test liquid in an amount of 0.05 mLis softly dropped by a micropipette on the fabric. If the dropletremains on the fabric after standing for 30 seconds, the test liquidpasses the test. The oil-repellency is expressed by a maximum point ofthe test liquid which passes the test. The oil-repellency is evaluatedas nine levels which are Fail, 1, 2, 3, 4, 5, 6, 7 and 8 in order of apoor level to an excellent level. TABLE 3 Oil-repellency test liquidSurface tension Point Test liquid (dyne/cm, 25° C.) 8 n-Heptane 20.0 7n-Octane 21.8 6 n-Decane 23.5 5 n-Dodecane 25.0 4 n-Tetradecane 26.7 3n-Hexadecane 27.3 2 Mixture liquid of 29.6 n-Hexadecane 35/nujol 65 1Nujol 31.2 Fail Inferior to 1 —Storage Stability Test

Test liquids (3 mass % in ethyl acetate) are prepared from polymersobtained in Preparative Examples and Comparative Preparative Examples.After the test liquid is left standing for 24 hours at room temperature(25° C.), the evaluation of sedimentation of the treatment liquid isobserved.

Good: No sedimentation

Fair: Slight sedimentation

Poor: Much sedimentation

Monomers were prepared as follows:

Preparative Example 1

Synthesis of 9F-Alc/αF Monomer

Into a 200 mL four-necked flask, 2-fluoroacrylic acid (19 g, 0.21 mol)and triethylamine (22.94 g, 0.23 mol) were charged. The atmosphere waspurged with nitrogen for 30 minutes with stirring. After the internaltemperature of the flask was decreased to 5° C. with ice,2-(perfluorobutyl)ethanol (9F-Alc) (54.52 g, 0.21 mol) was dropwiseadded for 4.5 hours so that a maximum of the internal temperature undernitrogen was 15° C. After the completion of the dropwise addition, thecooling with ice was continued for 30 minutes so that the exothermicreaction subsided and the internal temperature became 5° C. After theinternal temperature was increased to the room temperature, no increaseof the internal temperature was confirmed and the reaction was ripenedfor one hour. The reaction liquid was filtered and kept standing for onenight. The reaction liquid was neutralized with an aqueous 10% NaHCO₃solution and washed three times to give a dark brown liquid (54.00 g)(Yield 77.82%). The product was identified by ¹H-NMR, ¹⁹F-NMR and¹³C-NMR.

Preparative Example 2

Synthesis of 9F-Alc/αCl Monomer

Into a 200 mL four-necked flask, 2-chloroacrylic acid (20 g, 0.19 mol),2-(perfluorobutyl)ethanol (9F-Alc) (59.49 g, 0.23 mol), p-toluenesulfonic acid (1.06 g, 0.0056 mol), t-butyl catechol (0.16 g, 0.001 mol)and cyclohexane (90 g, 1.07 mol) were charged. The flask was heated sothat the internal temperature of the reactor was 80° C. The dehydrationcondensation reaction was conducted by using a Dean-Stark method. Thereaction was conducted for 16 hours. After the completion of thereaction, a small amount of brown sedimentations in the reaction liquidwere filtered off, the water washing was conducted three times. Then,the solvent and excess 9F-Alc were removed by an evaporator to give adark brown liquid (46.86 g) (Yield: 70.79%). The product was identifiedby ¹H-NMR, ¹⁹F-NMR and ¹³C-NMR.

Polymers were prepared as follows:

Preparative Example 3

Synthesis of 9F-Alc/αF Homopolymer

Into a 200 mL four-necked flask, the monomer synthesized in PreparativeExample 1 (9F-Alc/αF monomer) (15 g, 0.047 mol) andtetrachlorohexafluorobutane (S-316 manufactured by Daikin Industries,Ltd.) (121.45 g) were charged. After the solution was bubbled withnitrogen for 30 minutes, a gaseous phase was replaced with nitrogen for30 minutes. After the internal temperature was increased to 60° C., asolution of PERBUTYL PV 1.61 g (0.0092 mol) in trichloroethane (7.86 g)was added and the reaction was conducted for 6 hours. The reaction wasmonitored by a gas chromatography, and the disappearance of monomerpeaks was confirmed and regarded as the completion of the reaction.After the completion of the reaction, methanol was added to a solutioncontaining a polymer to precipitate a yellow precipitation. Theprecipitation was filtered under a reduced pressure and dried in avacuum desiccator to give a cream-colored flake solid (10.59 g) (Polymeryield: 70.60%). The polymer was identified by an elemental analysis(Table 4), ¹H-NMR, ¹⁹F-NMR and ¹³C-NMR.

Preparative Example 4

9F-Alc/αCl Homopolymer

Into a 100 mL four-necked flask, the monomer synthesized in PreparativeExample 2 (9F-Alc/αCl monomer) (10 g, 0.028 mol) andtetrachlorohexafluorobutane (S-316 manufactured by Daikin Industries,Ltd.) (80.95 g) were charged. After the solution was bubbled withnitrogen for 30 minutes, a gaseous phase was replaced with nitrogen for30 minutes. After the internal temperature was increased to 60° C., asolution of PERBUTYL PV 1.08 g (0.062 mol) in trichloroethane (5.24 g)was added and the reaction was conducted for 6 hours. The reaction wasmonitored by a gas chromatography, and the disappearance of monomerpeaks was confirmed and regarded as the completion of the reaction.After the completion of the reaction, methanol was added to a solutioncontaining a polymer to precipitate a white precipitation. Theprecipitation was filtered under a reduced pressure and dried in avacuum desiccator to give a white powder compound (8.17 g) (Polymeryield: 81.77%). The polymer was identified by an elemental analysis(Table 4), ¹H-NMR, ¹⁹F-NMR and ¹³C-NMR.

Preparative Example 5

9F-Alc/αF StA Copolymer

Into a 100 mL four-necked flask, the monomer synthesized in PreparativeExample 1 (9F-Alc/αF monomer) (7.00 g, 0.021 mol), stearyl acrylate(3.00 g, 0.0093 mol) and tetrachlorohexafluorobutane (S-316 manufacturedby Daikin Industries, Ltd.) (56.47 g) were charged. After the solutionwas bubbled with nitrogen for 30 minutes, a gaseous phase was replacedwith nitrogen for 30 minutes. After the internal temperature wasincreased to 60° C., a solution of PERBUTYL PV (0.75 g, 0.043 mol) intrichloroethane (3.67 g) was added and the reaction was conducted for 6hours. The reaction was monitored by a gas chromatography, and thedisappearance of peaks of the 9F-Alc/αF monomer and the stearyl acrylatemonomer was confirmed and regarded as the completion of the reaction.After the completion of the reaction, methanol was added to a solutioncontaining a polymer to precipitate a cream-colored precipitation. Theprecipitation was filtered under a reduced pressure and dried in avacuum desiccator to give a cream-colored rubbery compound (7.12 g)(Polymer yield: 71.2%). The polymer was identified by an elementalanalysis (Table 4), ¹H-NMR, ¹⁹F-NMR and ¹³C-NMR. The composition ofmonomers in the polymer was almost the same as the charged monomers.

Preparative Example 6

9F-Alc/αCl StA Copolymer

Into a 100 mL four-necked flask, the monomer synthesized in PreparativeExample 2 (9F-Alc/αCl monomer) (7.00 g, 0.020 mol), stearyl acrylate(3.00 g, 0.0093 mL) and tetrachlorohexafluorobutane (S-316 manufacturedby Daikin Industries, Ltd.) (56.47 g, 0.19 mol) were charged. After thesolution was bubbled with nitrogen for 30 minutes, a gaseous phase wasreplaced with nitrogen for 30 minutes. After the internal temperaturewas increased to 60° C., a solution of PERBUTYL PV (0.75 g, 0.043 mol)in trichloroethane (3.67 g) was added and the reaction was conducted for6 hours. Then, a solution of PERBUTYL PV (0.75 g, 0.043 mol) intrichloroethane (3.67 g) was further added and the reaction wasconducted for 6 hours.

The reaction was monitored by a gas chromatography, and thedisappearance of peaks of the 9F-Alc/αCl monomer and the stearylacrylate monomer was confirmed and regarded as the completion of thereaction. After the completion of the reaction, methanol was added to asolution containing a polymer to precipitate a white precipitation. Theprecipitation was filtered under a reduced pressure and dried in avacuum desiccator to give a white powder compound (7.86 g) (Polymeryield: 78.6%). The polymer was identified by an elemental analysis(Table 4), ¹H-NMR, ¹⁹F-NMR and ¹³C-NMR. The composition of monomers inthe polymer was almost the same as the charged monomers.

Comparative Preparative Example 1

9F-Alc/AA Homopolymer

Into a 200 mL four-necked flask, 2-(perfluorobutyl)ethyl acrylate(9F-Alc/AA) (R-1420 manufactured by Daikin Chemicals Sales Corporation)(15 g, 0.047 mol) and tetrachlorohexafluorobutane (S-316 manufactured byDaikin Industries, Ltd.) (121.45 g) were charged. After the solution wasbubbled with nitrogen for 30 minutes, a gaseous phase was replaced withnitrogen for 30 minutes. After the internal temperature of the flask wasincreased to 60° C., a solution of PERBUTYL PV (1.61 g, 0.0092 mol) intrichloroethane (7.86 g) was added and the reaction was conducted for 5hours. The reaction was monitored by a gas chromatography, and thedisappearance of monomer peaks was confirmed and regarded as thecompletion of the reaction. After the completion of the reaction,methanol was added to a solution containing a polymer to precipitate awhite starch syrup-like precipitation. A supernatant liquid was removedoff by decantation and a solvent was removed off from the precipitationby an evaporator to give a highly viscous transparent liquid compound(9.36 g) (Polymer yield: 62.40%). The polymer was identified by anelemental analysis (Table 4), ¹H-NMR, ¹⁹F-NMR and ¹³C-NMR.

Comparative Preparative Example 2

17F-Alc/AA Homopolymer

Into a 200 mL four-necked flask, 2-(perfluorooctyl)ethyl acrylate(17F-Alc/AA) (R-1820 manufactured by Daikin Chemicals Sales Corporation)(15 g, 0.03 mol) and tetrachlorohexafluorobutane (S-316 manufactured byDaikin Industries, Ltd.) (121.45 g, 0.40 mol) were charged. After thesolution was bubbled with nitrogen for 30 minutes, a gaseous phase wasreplaced with nitrogen for 30 minutes. After the internal temperature ofthe flask was increased to 60° C., a solution of PERBUTYL PV (1.61 g,0.0092 mol) in trichloroethane (7.86 g) was added and the reaction wasconducted for 5 hours. The reaction was monitored by a gaschromatography, and the disappearance of monomer peaks was confirmed andregarded as the completion of the reaction. After the completion of thereaction, methanol was added to a solution containing a polymer toprecipitate a white precipitation. The precipitation was filtered undera reduced pressure and dried in a vacuum desiccator to give a whitepowdery compound (12.55 g) (Polymer yield: 83.33%). The polymer wasidentified by an elemental analysis (Table 4), ¹H-NMR, ¹⁹F-NMR and¹³C-NMR.

Comparative Preparative Example 3

9F-Alc/AA StA Copolymer

Into a 100 mL four-necked flask, 2-(perfluorobutyl)ethyl acrylate(9F-Alc/AA) (R-1420 manufactured by Daikin Chemicals Sales Corporation)(7.00 g, 0.022 mol), stearyl acrylate (3.00 g, 0.0093 mol) andtetrachlorohexafluorobutane (S-316 manufactured by Daikin Industries,Ltd.) (56.47 g, 0.19 mol) were charged. After the solution was bubbledwith nitrogen for 30 minutes, a gaseous phase was replaced with nitrogenfor 30 minutes. After the internal temperature of the flask wasincreased to 60° C., a solution of PERBUTYL PV (0.75 g, 0.0043 mol) intrichloroethane (3.67 g) was added, the reaction was conducted for 6hours. Then a solution of PERBUTYL PV (0.75 g, 0.0043 mol) intrichloroethane (3.67 g) was further added and the reaction wasconducted for 6 hours. The reaction was monitored by a gaschromatography, and the disappearance of peaks of the 9F-Alc/AA monomerand the stearyl acrylate monomer was confirmed and regarded as thecompletion of the reaction. After the completion of the reaction,methanol was added to a solution containing a polymer to precipitate awhite precipitation. A supernatant liquid was removed off by decantationand a solvent was removed off from the precipitation by an evaporator togive a highly viscous opaque liquid compound (7.06 g) (Polymer yield:70.60%). The polymer was identified by an elemental analysis (Table 4),¹H-NMR, 19F-NMR and ¹³C-NMR. The composition of monomers in the polymerwas almost the same as the charged monomers.

Comparative Preparative Example 4

17F-Alc/AA StA Copolymer

Into a 200 mL four-necked flask, 2-(perfluorooctyl)ethyl acrylate(17F-Alc/AA) (R-1820 manufactured by Daikin Chemicals Sales Corporation)(21.00 g, 0.041 mol), stearyl acrylate (9.00 g, 0.028 mol) andtetrachlorohexafluorobutane (S-316 manufactured by Daikin Industries,Ltd.) (170.00 g, 0.56 mol) were charged. After the solution was bubbledwith nitrogen for 30 minutes, a gaseous phase was replaced with nitrogenfor 30 minutes. After the internal temperature of the flask wasincreased to 60° C., a solution of PERBUTYL PV (2.25 g, 0.013 mol) intrichloroethane (11.00 g) was added, the reaction was conducted for 5hours. Then a solution of PERBUTYL PV (0.75 g, 0.0043 mol) intrichloroethane (3.67 g, 0.027 mol) was further added and the reactionwas conducted for 5 hours. The reaction was monitored by a gaschromatography, and the disappearance of peaks of the 17F-Alc/AA monomerand the stearyl acrylate monomer was confirmed and regarded as thecompletion of the reaction. After the completion of the reaction,methanol was added to a solution containing a polymer to precipitate awhite precipitation. The white precipitation was filtered under areduced pressure and dried in a vacuum desiccator to give a whitepowdery compound (27.07 g) (Polymer yield: 90.23%). The polymer wasidentified by an elemental analysis (Table 4), ¹H-NMR, ¹⁹F-NMR and¹³C-NMR. The composition of monomers in the polymer was almost the sameas the charged monomers.

Comparative Preparative Example 5

Synthesis of 17F-Alc/αCl Monomer

In a 500 ml shaded four-necked flask, 2-(perfluorooctyl)ethyl acrylate(17F-Alc/AA) (R-1820 manufactured by Daikin Chemicals Sales Corporation)(251 g, 484 mmol), triethylamine (1.47 g, 14.5 mmol),t-butylcatechol(0.1 g) were charged. Chlorine was blown into the flask at a temperaturebetween room temperature and 50° C. for 17 hours to give a dichlorocompound (285 g).

According to a gas chromatography analysis, the conversion was 100% andthe selectivity of the dichloro compound was 97% (G.C. Area). Thestructure of the object compound was confirmed by ¹H-NMR.

Then chloroform (640 g) and t-butylcatechol (0.1 g) were charged into a2 L Erlenmeyer flask and triethylamine was (58.7 g, 581 mmol) was addedwhile cooling with ice. When the exothermic heat was relieved, thedichloro compound (285 g, 484 mmol, G.C. purity: 97%) was graduallyadded while cooling with ice. After the whole amount of the dichlorocompound was added, the dichloro compound was reacted at roomtemperature for about 30 minutes. The disappearance of the dichlorocompound was confirmed by a gas chromatography.

The mixture was washed with water to eliminate a triethylaminehydrochloride salt and evaporated to eliminate chloroform, giving abrown solid (224 g, yield: 84%). The product was identified by ¹H-NMR,¹⁹F-NMR and

¹³C-NMR.

Comparative Preparative Example 6

17F-Alc/αCl Homopolymer

Into a 100 mL four-necked flask, the 17F-Alc/αCl monomer (15 g, 0.027mol) synthesized in Comparative Preparative Example 5 andtetrachlorohexafluorobutane (S-316 manufactured by Daikin Industries,Ltd.) (121.4 g) were charged. After the solution was bubbled withnitrogen for 30 minutes, a gaseous phase was replaced with nitrogen for30 minutes. After the internal temperature of the flask was increased to60° C., a solution of PERBUTYL PV (1.61 g, 0.0067 mol) intrichloroethane (5 g) was added and the reaction was conducted for 4hours. Then a solution of PERBUTYL PV (0.32 g, 0.0013 mol) intrichloroethane (2 g) was further added and the reaction was conductedfor 1 hour. The reaction was monitored by a gas chromatography, and thedisappearance of monomer peaks was confirmed and regarded as thecompletion of the reaction. After the completion of the reaction,methanol was added to a solution containing a polymer to precipitate awhite precipitation. The precipitation was filtered under a reducedpressure and dried in a vacuum desiccator to give a white powderycompound (12.4 g) (Polymer yield: 83%). The polymer was identified by¹H-NMR, ¹⁹F-NMR and ¹³C-NMR.

Comparative Preparative Example 7

17F-Alc/αCl StA Copolymer

Into a 100 mL four-necked flask, the 17F-Alc/αCl monomer (14 g, 0.025mol) synthesized in Comparative Preparative Example 5, stearyl acrylate(6.00 g, 0.019 mol) and tetrachlorohexafluorobutane (S-316 manufacturedby Daikin Industries, Ltd.) (113.3 g, 0.373 mol) were charged. After thesolution was bubbled with nitrogen for 30 minutes, a gaseous phase wasreplaced with nitrogen for 30 minutes. After the internal temperature ofthe flask was increased to 60° C., a solution of PERBUTYL PV (1.5 g,0.0062 mol) in trichloroethane (5 g) was added and the reaction wasconducted for 4 hours. Then a solution of PERBUTYL PV (0.3 g, 0.0012mol) in trichloroethane (3 g) was further added and the reaction wasconducted for 6 hours. After the completion of the reaction, methanolwas added to a solution containing a polymer to precipitate a whiteprecipitation. The precipitation was filtered under a reduced pressureand dried in a vacuum desiccator to give a white powdery compound (17.2g) (Polymer yield: 86%). The polymer was identified by ¹H-NMR, ¹⁹F-NMRand ¹³C-NMR. The composition of monomers in the polymer was almost thesame as the charged monomers.

Example 1

The polymer (6 g) obtained in Preparative Example 3 was dissolved inHCFC225 (600 g). After three nylon test fabrics (510 mm×205 mm) wereimmersed in this test solution (150 g) for about 5 minutes, and thesolvent was removed by centrifugal dehydrator (500 rpm, 20 seconds) Thesame procedure was conducted for three PET test fabrics (510 mm×205 mm),three PET/cotton mixture test fabrics (510 mm×205 mm) and three cottontest fabrics (510 mm×205 mm). Then each test fabric was dried at 28° C.for one night.

Then, each one fabric from nylon test fabrics, PET test fabrics,PET/cotton mixture test fabrics and cotton test fabrics was treated by apin tenter at 80° C. for 3 minutes, and each fabric was cut into halves(255 mm×205 mm). One half was used for a shower water repellency test,and the other half was used for a water repellency test and an oilrepellency test.

Then, each one fabric from nylon test fabrics, PET test fabrics,PET/cotton mixture test fabrics and cotton test fabrics was treated by apin tenter at 150° C. for 3 minutes, and each fabric was cut into halves(255 mm×205 mm). One half was used for a shower water repellency test,and the other half was used for a water repellency test and an oilrepellency test.

Remaining nylon test fabric, PET test fabric, PET/cotton mixture testfabric and cotton test fabric were not subjected to the heat treatment,and were cut into halves (255 mm×205 mm). One half was used for a showerwater repellency test, and the other half was used for a waterrepellency test and an oil repellency test. The test results are shownin Table 5.

Storage stability of a 3 weight % concentration solution of the polymerin ethyl acetate stored at 25° C. for 24 hours was also measured. Theresults are shown in Table 6.

Example 2

The polymer obtained in Preparative Example 4 was treated as in Example1, and then subjected to the shower water repellency test, the waterrepellency test and the oil repellency test. The test results are shownin Table 5.

The storage stability was also measured. The results are shown in Table6.

Example 3

The polymer obtained in Preparative Example 5 was treated as in Example1, and then subjected to the shower water repellency test, the waterrepellency test and the oil repellency test. The test results are shownin Table 5.

The storage stability was also measured. The results are shown in Table6.

Example 4

The polymer obtained in Preparative Example 6 was treated as in Example1, and then subjected to the shower water repellency test, the waterrepellency test and the oil repellency test. The test results are shownin Table 5.

The storage stability was also measured. The results are shown in Table6.

Example 5

The 9F-Alc/αF monomer synthesized in Preparative Example 1 was dissolvedin each of isopropyl alcohol, toluene, n-heptane, mineral spirit, methylmethacrylate, ethyl methacrylate and glycidyl methacrylate to give asolution having a concentration of 3 mass % and the solution was left tostand at room temperature (25° C.) for 24 hours. The evolution ofsedimentation was observed. The criteria of the evaluation were the sameas the storage stability test. The results are shown in Table 7.

The 9F-Alc/αCl monomer synthesized in Preparative Example2,2-(perfluorobutyl)ethyl acrylate (9F-Alc/AA) (R-1420 manufactured byDaikin Chemicals Sales Corporation) used in Comparative PreparativeExample 1, perfluoroacrylate monomer[CF₃CF₂(CF₂CF₂)_(n)CH₂CH₂OC(═O)CH═CH₂ (a mixture of compounds whereinn=3, 4, 5, 6 and 7 in amounts of 50 mass %, 25 mass %, 12 mass %, 6 mass% and 3 mass %)] (17F-Alc/AA) also were subjected to the solubility testin the same manner. The results are shown in Table 7.

Comparative Example 1

The polymer obtained in Comparative Preparative Example 1 was treated asin Example 1, and then subjected to the shower water repellency test,the water repellency test and the oil repellency test. The test resultsare shown in Table 5.

The storage stability of the test solution also was measured. Theresults are shown in Table 6.

Comparative Example 2

The polymer obtained in Comparative Preparative Example 2 was subjectedto the storage stability test of the test solution. The results areshown in Table 6.

Comparative Example 3

The polymer obtained in Comparative Preparative Example 3 was treated asin Example 1, and then subjected to the shower water repellency test,the water repellency test and the oil repellency test. The test resultsare shown in Table 5.

The storage stability of the test solution also was measured. Theresults are shown in Table 6.

Comparative Example 4

The polymer obtained in Comparative Preparative Example 4 was subjectedto the storage stability test of the test solution. The results areshown in Table 6.

Comparative Example 5

The polymer obtained in Comparative Preparative Example 6 (6 g) wasdissolved in HCFC 225 (600 g). After three nylon test fabrics (510mm×205 mm) were immersed in this test solution (150 g) for about 5minutes, and the solvent was removed by centrifugal dehydrator (500 rpm,20 seconds). Then each test fabric was dried at 28° C. for one night.

Then, each of test fabrics was treated by a pin tenter at 150° C. for 3minutes, each fabric was cut into halves (255 mm×205 mm). One half wasused for a shower water repellency test, and the other half was used fora water repellency test and an oil repellency test.

The test results are shown in Table 8.

Comparative Example 6

The polymer obtained in Comparative Preparative Example 7 was treated asin Comparative Example 5, and then subjected to the shower waterrepellency test, the water repellency test and the oil repellency test.The test results are shown in Table 8. TABLE 4 Comparative ComparativeComparative Comparative Elemental Preparative Preparative PreparativePreparative Preparative Preparative Preparative Preparative AnalysisExample 3 Example 4 Example 5 Example 6 Example 1 Example 2 Example 3Example 4 F Found (%) 55.01 47.32 37.72 31.95 49.74 57.80 35.97 42.12Calculated (%) 56.55 48.51 39.58 33.96 53.77 62.37 37.64 43.65 C Found(%) 31.33 31.17 45.42 46.39 33.67 30.28 42.85 44.05 Calculated (%) 32.1430.64 45.83 44.78 33.96 30.12 47.11 44.41 H Found (%) 1.89 2.09 4.964.57 2.21 1.58 4.45 4.21 Calculated (%) 1.79 1.70 4.95 4.90 2.20 1.355.24 4.65 N Found (%) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Calculated(%) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Cl Found (%) 0.00 10.69 0.006.67 0.00 0.00 0.00 0.00 Calculated (%) 0.00 10.07 0.00 7.05 0.00 0.000.00 0.00

TABLE 5 Test Treatment Shower water Water Shower water Water fabrictemperature repellency repellency Oil repellency repellency repellencyOil repellency Example 1 Example 2 Nylon RT 70 3 2 80 5 6  80° C. 50 3 280 5 6 150° C. 70 7 6 90 9 7 PET RT 50 3 1 70 6 6  80° C. 50 4 2 80 6 6150° C. 70 6 3 100 7 6 PET/ RT 50 5 1 50 7 3 Cotton  80° C. 50 7 1 70 84 150° C. 70 7 1 80 9 4 Cotton RT 50 9 4 50 7 3  80° C. 50 9 4 50 7 4150° C. 50 9 5 50 8 5 Example 3 Example 4 Nylon RT 70 8 6 90 8 6  80° C.80 9 6 100 10 6 150° C. 80 9 6 100 10 6 PET RT 70 6 3 80 8 4  80° C. 706 4 90 8 5 150° C. 80 6 4 100 9 6 PET/ RT 50 8 4 70 6 4 Cotton  80° C.70 9 4 80 6 6 150° C. 70 9 5 100 6 6 Cotton RT 50 9 4 50 6 4  80° C. 509 4 50 6 6 150° C. 50 9 4 90 6 6 Comparative Example 1 ComparativeExample 3 Nylon RT 50 2 0 70 5 2  80° C. 50 3 0 70 5 2 150° C. 50 3 0 705 2 PET RT 3 5 50 5 3 3  80° C. 70 3 5 50 5 3 150° C. 70 3 5 50 5 3 PET/RT 0 2 2 0 3 2 Cotton  80° C. 0 2 2 0 3 2 150° C. 0 3 3 50 5 2 Cotton RT0 0 3 0 2 2  80° C. 0 0 3 0 2 2 150° C. 0 Fail 4 0 6 2

TABLE 6 Storage stability Example 1 Good Example 2 Good Example 3 GoodExample 4 Good Comparative Example 1 Good Comparative Example 2 PoorComparative Example 3 Good Comparative Example 4 Poor

TABLE 7 9F-Alc/αF 9F-Alc/αCl 9F-Alc/AA 17F-Alc/AA Isopropyl alcohol GoodGood Good Poor Toluene Good Good Good Poor n-Heptane Good Good Good FairMineral spirit Good Good Good Poor Methyl Good Good Good Fairmethacrylate Ethyl Good Good Good Fair methacrylate Glycidyl Good GoodGood Poor methacrylate (Blemmer G)

TABLE 8 17FCA 17FClA/StA Comparative Comparative Example 5 Example 69FClA 9FClA/StA Name Shower Shower Example 2 Example 4 Evalua- Treat-water Oil water Water Oil Shower Water Shower tion of ment re- Water re-re- re- re- water re- Oil water Water Oil Properties temp. pellencyrepellecy pellecy pellency pellecy pellecy pellency repellecy repellecyrepellency repellecy repellecy Cotton 150° C. 70 8 5 50 6 5 100 8 5 90 66

1. A surface treatment agent comprising a fluorine-containing polymercomprising: (A) repeating units derived from a fluorine-containingmonomer of the formula:

wherein X is a fluorine atom, a chlorine atom, a bromine atom, a iodineatom, a CFX¹X² group (wherein each of X¹ and X² is a hydrogen atom, afluorine atom or a chlorine atom), a cyano group, a linear or branchedfluoroalkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted benzyl group, or a substituted or unsubstituted phenylgroup, Y is an aliphatic group having 1 to 10 carbon atoms, an aromaticor cycloaliphatic group having 6 to 10 carbon atoms, a —CH₂CH₂N(R¹)SO₂—group (wherein R¹ is an alkyl group having 1 to 4 carbon atoms) or a—CH₂CH(OY¹)CH₂— group (wherein Y¹ is a hydrogen atom or an acetylgroup), and Rf is a linear or branched fluoroalkyl group having 1 to 6carbon atoms, (B) repeating units derived from a monomer free from afluorine atom, and (C) optionally present, repeating units derived froma crosslinkable monomer.
 2. The surface treatment agent according toclaim 1, wherein the Rf group in the repeating units (A) has 1 to 4carbon atoms.
 3. The surface treatment agent according to claim 1,wherein the Rf group in the repeating units (A) is a perfluoroalkylgroup.
 4. The surface treatment agent according to claim 1, wherein thefluorine atom-free monomer constituting the repeating units (B) isacrylates of the general formula:CH₂═CA¹COOA² wherein A¹ is a hydrogen atom or a methyl group, and A² isa hydrocarbon group having 1 to 30 carbon atoms (particularly an alkylgroup represented by C_(n)H_(2n+1) (n is 1 to 30)).
 5. The surfacetreatment agent according to claim 1, wherein the crosslinkable monomerconstituting the repeating units (C) is a fluorine-free monomer havingat least two reactive groups and/or carbon-carbon double bonds.
 6. Thesurface treatment agent according to claim 1, wherein, in thefluorine-containing polymer, the amount of the fluorine atom-freemonomer is from 0.1 to 50 parts by weight, and the amount of thecrosslinkable monomer is at most 20 parts by weight, based on 100 partsby weight of the fluorine-containing monomer.
 7. The surface treatmentagent according to claim 1, wherein the Rf group is a perfluoroalkylgroup.
 8. The surface treatment agent according to claim 1, which is inthe form of a solution, an emulsion or an aerosol.
 9. Afluorine-containing polymer comprising: (A) repeating units derived froma fluorine-containing monomer of the formula:

wherein X is a fluorine atom, a chlorine atom, a bromine atom, a iodineatom, a CFX¹X² group (wherein each of X¹ and X² is a hydrogen atom or afluorine atom), a cyano group, a linear or branched fluoroalkyl grouphaving 1 to 6 carbon atoms, a substituted or unsubstituted benzyl group,or a substituted or unsubstituted phenyl group, Y is an aliphatic grouphaving 1 to 10 carbon atoms, an aromatic or cycloaliphatic group having6 to 10 carbon atoms, a —CH₂CH₂N(R¹)SO₂— group (wherein R¹ is an alkylgroup having 1 to 4 carbon atoms) or a —CH₂CH(OY¹)CH₂— group (wherein Y¹is a hydrogen atom or an acetyl group), and Rf is a linear or branchedfluoroalkyl group having 1 to 4 carbon atoms, (B) repeating unitsderived from a monomer free from a fluorine atom, and (C) optionallypresent, repeating units derived from a crosslinkable monomer.
 10. Amethod of treating a substrate with the surface treatment agentaccording to claim
 1. 11. The method according to claim 10, wherein thesubstrate is a textile, a masonry, a filter (for example, anelectrostatic filter), a dust protective mask, a fuel cell, glass,paper, wood, leather, fur, asbestos, brick, cement, metal and oxide,ceramics, plastics, a coated surface or a plaster.
 12. A textile whichis treated with the surface treatment agent according to claim
 1. 13. Acarpet which is treated with the surface treatment agent according toclaim 1.